Safety switch



July 15, 1958 F. w. MURPHY 2,843,687

' SAFETY SWITCH Filed July 31, 1956.

INVENIOR RWMW hI;

ATTORNE S United States Patent SAFETY SWITCH Frank W. Murphy,Tulsa,'0kla.

Application July 31, 1956, Serial No. 601,194

' Claims. Cl. 200-56) The present invention relates to safety switches,and more particularly to such switches combined with a gauge andresponsive to conditions of said gauge.

The primary object of the invention is to provide .a safety switch whichis actuated by the movable gauge indicator upon a predetermined movementthereof.

Another object of the invention is to provide a safety switch of theclass described above having means to adjust the position of the switchso as to vary the condition under which the switch will operate.

A further object of the invention is to provide a safety switch of theclass described above which is inexpensive to manufacture, simple touse, and completely effective and accurate in its operation.

Other objects and advantages will become apparent in the followingspecification when considered in the light of the attached drawings, inwhich:

Figure l is a plan view of the invention with parts broken away insection for clarity of illustration.

Figure 2 is a fragmentary enlarged vertical crosssection taken along theline 22 of Figure 1, looking in the direction indicated.

Figure 3 is a diagrammatic view of the invention illustrating theelectrical circuit used therewith.

Figure 4 is a plan view of the switch support blank used with theinvention.

Referring now to the drawings in detail wherein like referencecharacters indicate like parts throughout the several figures, thereference numeral indicates generally a combined safety switch and gaugeconstructed in accordance with the invention.

The combination gauge and safety switch 10 comprises a generallycylindrical body 11 having a bottom wall 12,

a dial 13 positioned in vertically spaced relation to the bottom 12, aglass 14 positioned above the dial 13, and a glass retainer ring 15securing the glass 14 to the cylindrical body 11. An indicator hand 16is pivoted at 17 in the cylindrical body 11 and has secured theretobeneath the dial 13 an actuating pin 18, as best seen in Figure l.

The indicator hand 16 is adapted to swing on the pivot 17 carrying theactuating pin 18 therewith. The indicator hand 16 is adapted to bedriven by any suitable means (not shown) in response to pressurechanges, temperature changes, or any other measured phenomenon.

A switch plate, generally indicated at 19, rests on the bottom 12 of thecylindrical body 11 and is pivoted thereto by means of a pivot bolt 20extending through a bore 21 in one end of the switch plate 19. Theopposite end of the switch plate 19 is provided with a generallyU-shaped bracket 22 having an outer vertical wall 23 carrying avertically extending slot 24 therein. The switch plate 19 is providedwith a laterally extending support 25 having a bore 26extending'therethrough.

An arm 27 is provided with a horizontal fiange 28 having a pivot bolt 29extending therethrough into the bore 26 of the extension 25 to pivotallymount the arm 27 to the extension 25. The end of the arm 27 opposite theflange 28 is provided with an offset extensionSfl which is adapted toengage the actuating pin 18 carried by the indicator hand 16, as bestshown in Figure 1.

A micro switch 31 is secured .to the switch plate 19 by means of 'bolts32 extending therethrough and into bores 33 in the switch plate 19. Themicro switch 31 is of conventional construction and has a plurality ofterminal connectors '34, 35 and 36 on one end thereof, a conventionalswinging switch arm 37 'interiorly thereof, and a switch arm actuatingpin 38 extending through the side Wall of the micro switch 31 to engagethe arm 27, as best seen in Figure 1.

The cylindrical body 11 has a flattened portion 3.9 formed in one sidethereof with a bore 40 extending therethrough. A bolt 41 having a head42 on the outer end thereof extends through the bore 40 into thecylindrical body 11 and through the slot 24 in the outer wall 23 of theU-shaped bracket 22. A head 43 is formed on the inner end of the bolt 41and is positioned behind the vertical wall 23 so as to rotatably securethe bolt 41 to the bracket 22.

A nut 44 is engaged on the bolt 41 exteriorly of the cylindrical body 11in engagement therewith so that the nut 44 engages a shoulder 45 on thebody 11 so as to be held against turning. A coil spring 46 is positionedabout the bolt 41 interiorly of the body 11 having one end thereof inengagement with the body 11 and the other end thereof in engagement withthe vertical wall 23 of the bracket 22.

As can be readily seen by reference to Figure l, the bolt 41 by means ofhead 42 will swing the switch plate 19 about the pivot 20 to move theswitch actuating bar 38 toward and away from the actuating pin 18. Thespring 46 will normally maintain the nut 45 in tight engagement with thebody 11 so that the switch 31 will be normally maintained in theinnermost position permitted by the nut 45.

In the use and operation of the invention, the indicator hand 16 inresponse to exterior forces rotates on the pivot 17 carrying theactuating pin 18 therewith. The actuating pin 18 in contact with theoffset portion 30 of the arm 27 causes the arm 27 to pivot about thepivot 29 moving the switch arm 38 so as to actuate the switch 31 andbreak a circuit existing between the contacts 34 and 36.

As the indicator hand 16 reverses its direction of movement, theindicator pin 18 will permit the arm 27 to move away from the switch 31so that the switch will again close the circuit between the contacts 34and 36.

In the event that the indicator hand 16 continues to travel after thearm 27 has pivoted to it fullest extent on the pivot 29, the switchplate 19 will swing on the pivot 20 against the tension of the spring 46to move the switch 31 permitting the arm 27 as far as is necessary bythe movement of the actuating pin 18.

It should be noted that the switch 31 can be utilized to actuate a motor47 through a battery 48 utilizing the contacts 34 and 36 so that thebreaking of the circuit between the contacts 34 and 36 will cause themotor 47 to cease to run. Obviously, the use of the contacts 34 and 35will establish a circuit upon movement of the switch arm 37 when such anaction is desired.

Having thus described the preferred embodiment of the invention, itshould be understood that numerous structural modifications andadaptations may be resorted to without departing from the scope of theappended claims.

What is claimed is:

1. A combined gauge and safety switch comprising a gauge body, anindicator hand pivotally mounted in said gauge body, a switch pivotallymounted to said gauge body for movement in a direction toward saidindicator hand, a switch actuating arm pivotally carried by said switchfor movement in a direction toward said indicator hand, a switchactuating arm actuating pin carried by said indicator hand for .movingsaid actuating arm to switch actuating position upon movement of saidindicator hand.

2. A device as claimed in claim 1 wherein said switch is biased towardsaid indicator hand by means of a spring biasing means.

3. A device as claimed in claim 2 wherein a screw threaded adjustingmeans is associated with said switch and said spring biasing means toadjust the pivotal position of said switch.

4. A safety switch for gauges of the type having a gauge body and apivoted indicator hand comprising a 15 switch pivotally mounted in saidgauge body, means including a spring for normally maintaining saidpivoted switch in one position, a switch actuating arm pivoted to saidswitch, .an actuating pin carried by the indicator hand of said gaugeand engaging said actuating arm whereby rotational movement of said handwill pivot said actuating arm on said switch actuating said switch, saidspring biasing means permitting pivotal movement of said switchthereagainst upon pivotal action of said indicator hand beyond thatnecessary to actuate said switch.

5. A device as claimed in claim 4 wherein said adjusting means for saidswitch extends through said body for operation exteriorly of said body.

References Cited in the file of this patent UNITED STATES PATENTS

